High third-order nonlinear optical susceptibility in new fluorinated poly( p-phenylenevinylene) copolymers measured with the Z-scan technique

The third-order nonlinear optical properties of a series of copoly(2,3,5,6-tetraf luoro-1,4-phenylenevinylene- 2,5-dioctyloxy-1,4-phenylenevinylene) that contain variable ratios of two differently substituted monomers have been studied in chloroform solutions at l 1064 nm by the picosecond Z-scan technique. Nonlinear refractive index n2 of the samples investigated has been found to be negative, and a strong dependence of its magnitude on the copolymer's composition has been observed. The highest third-order nonlinear optical susceptibility, jx3j 6 6 2 3 10210 esu, was measured for a copolymer obtained by reaction of equimolar quantitites of the parent monomers.